Abstract
We show that upon Tb substitution the interaction between the magnetic moments on the impurity ion and its surrounding ions is described by a “compass” model, i.e., an Ising-like interaction favoring the magnetic moments across each bond to align along the bond direction. Such an interaction nucleates quenched magnetic vortices near the impurities and drives a reentrant transition out of the antiferromagnetic ordered phase at low temperatures, hence quickly suppressing the Néel temperature, consistent with the experiment [J. C. Wang et al., Phys. Rev. B 92, 214411 (2015)]. As a by-product, we propose that the compass model can be realized in ordered double perovskites composed of spin-orbital-coupled ions and half-closed-shell ions.
- Received 19 July 2016
- Revised 25 September 2016
DOI:https://doi.org/10.1103/PhysRevB.94.161118
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